Improve returning of header block groups. * Introduce a custom Iterator to do traversals. This ensures that we're not walking unnecessarily through the entire structure, and also makes sure that only SOAPHeaderBlocks are included in the results. * Adjust tests accordingly (remove unnecessary next() calls, etc) * Fix a few spelling errors
webservices/commons/trunk/modules/axiom/modules/axiom-impl/src/main/java/org/apache/axiom/soap/impl/llom/SOAPHeaderImpl.java